Diarrhoea is one of the major causes of morbidity and mortality in the world, and in developing countries it accounts for more infant fatalities than any other single cause. Even in North America and Europe it is a leading reason for death or debilitation among both the young and the elderly. Severe diarrhoea is most commonly caused by an infection of the small intestine; however, the microorganism itself does not invade the intestinal mucosa but produces an enterotoxin which is believed to be responsible for stimulating active electrolyte secretion and consequent fluid loss.
Although the introduction of oral hydration therapy has greatly simplified the treatment of dehydrating diarrhoea, drugs that reduce the rate of fluid loss also have an important role in the management of the condition. One such drug which has recently been identified as a promising antisecretory drug for use in the treatment of dehydrating diarrhoea is chlorpromazine ("Secretary Diarrhea", American Physiological Society (1980), pp 211-218. However, chlorpromazine also has marked effects on the central nervous system at the dosages used, most notably sedation. The present invention provides compounds which are useful in the treatment of diarrhoea but which have significantly reduced sedative effects.
Certain phenylbenzo[b]thiophenes having anti-inflammatory properties are disclosed in U.S. Pat. No. 3,598,839.
Other benzothiophene compounds, useful as antimicrobial agents are disclosed in U.S. Pat. Nos. 3,944,672 and 4,018,893.
U.S. Pat. No. 4,137,414 discloses certain 5-substituted-2-phenylbenzo[b]thiophene-3-alkylamines, useful as neuroleptics or antibacterial agents.